o Solder provides both mechanical support and electrical connectivity, and is widely associated with the manufacture of electrical and electronic circuits. Preferred soldering methods in these industries include hand soldering and machine soldering. Plumbers and automotive engineers use solder to join and seal pipes and radiators, generally using manual methods including gas soldering. Solder also plays a significant role in the creation of art and jewelry, where manual soldering techniques join precious metals, including gold and silver.